From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934060Ab1ETCNz (ORCPT ); Thu, 19 May 2011 22:13:55 -0400 Received: from gate.crashing.org ([63.228.1.57]:60118 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754851Ab1ETCNy (ORCPT ); Thu, 19 May 2011 22:13:54 -0400 Subject: Re: [bg-linux] [PATCH 5/7] [RFC] force 32-byte aligned kmallocs From: Benjamin Herrenschmidt To: Kazutomo Yoshii Cc: Eric Van Hensbergen , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, bg-linux@lists.anl-external.org In-Reply-To: <1305857301.7481.121.camel@pasglop> References: <1305753895-24845-1-git-send-email-ericvh@gmail.com> <1305753895-24845-5-git-send-email-ericvh@gmail.com> <1305851769.7481.90.camel@pasglop> <4DD5C49E.4050103@gmail.com> <1305857301.7481.121.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 20 May 2011 12:13:30 +1000 Message-ID: <1305857610.7481.124.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-05-20 at 12:08 +1000, Benjamin Herrenschmidt wrote: > On Thu, 2011-05-19 at 20:32 -0500, Kazutomo Yoshii wrote: > > > > Actually DMA sends invalidate requests to the snoop unit(L2 level). > > BGP SoC is a bit different from other 4xx base. > > Well, some other 44x also have a snooping L2 (more or less), but L1 is > usually the problem. Hrm... looking at the doco you pointed me to, it looks like the L1 -is- coherent, it gets snoop kills from the L2. Ok so we do need to make this non-coherent cache stuff a runtime option (well, we need that for 440+476 too anyways so may as well do it now). As for the alignment of kmalloc, it looks like a hack that should be done in the torus code itself. Cheers, Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 51C79B71CE for ; Fri, 20 May 2011 12:13:52 +1000 (EST) Subject: Re: [bg-linux] [PATCH 5/7] [RFC] force 32-byte aligned kmallocs From: Benjamin Herrenschmidt To: Kazutomo Yoshii In-Reply-To: <1305857301.7481.121.camel@pasglop> References: <1305753895-24845-1-git-send-email-ericvh@gmail.com> <1305753895-24845-5-git-send-email-ericvh@gmail.com> <1305851769.7481.90.camel@pasglop> <4DD5C49E.4050103@gmail.com> <1305857301.7481.121.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 20 May 2011 12:13:30 +1000 Message-ID: <1305857610.7481.124.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, bg-linux@lists.anl-external.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2011-05-20 at 12:08 +1000, Benjamin Herrenschmidt wrote: > On Thu, 2011-05-19 at 20:32 -0500, Kazutomo Yoshii wrote: > > > > Actually DMA sends invalidate requests to the snoop unit(L2 level). > > BGP SoC is a bit different from other 4xx base. > > Well, some other 44x also have a snooping L2 (more or less), but L1 is > usually the problem. Hrm... looking at the doco you pointed me to, it looks like the L1 -is- coherent, it gets snoop kills from the L2. Ok so we do need to make this non-coherent cache stuff a runtime option (well, we need that for 440+476 too anyways so may as well do it now). As for the alignment of kmalloc, it looks like a hack that should be done in the torus code itself. Cheers, Ben.